Section 6. To provide for extraordinary or unforeseen expenditures, a town may at an annual or special town meeting appropriate or transfer a sum or sums not exceeding in the aggregate five per cent of the levy of the fiscal year preceding the fiscal year for which the fund, to be known as the reserve fund, is established. No direct drafts against this fund shall be made, but transfers from the fund may from time to time be voted by the finance or appropriation committee of the town, in towns having such a committee, and in other towns by the selectmen; and the town accountant in towns having such an official, and in other towns the auditor or board of auditors, shall make such transfers accordingly.